Growing dahlia in zone 9a
(Zone 9a = an average winter low of 20°F to 25°F.)
In USDA zone 9a, the typical last spring frost is March 2 and the first fall frost is November 26. Here is when to plant dahlia against those dates.
Typical timing
Zone 9a planting schedule
Evidence trail
How these dates are built
Sprout applies the cited planting offsets to the typical zone 9a frost anchors. The result is a planning baseline for the zone, not a local weather forecast.
- USDA Plant Hardiness Zone Map, 2023USDA Agricultural Research Service / Oregon State University PRISM Group. Supports the USDA hardiness-zone band.
- U.S. Climate Normals 1991-2020NOAA National Centers for Environmental Information. Supports the median spring and fall freeze dates.
- The Dirt on DahliasPenn State Extension. Supports outdoor transplant timing (normalized).
Method note
Tuber planting after spring frost danger (start-only anchor expressed as weeks 0-2), depth 4 to 6 inches (4 recorded), full sun, deer browsing, winter tuber storage at 32 to 50 F to prevent rot. Lifecycle recorded as annual because PSU directs digging the tender tubers every fall after a hard frost. No spacing, pH, or water-rate numbers given, so those fields are omitted.
These are zone 9a averages
Computed from 2,196 ZIP codes in zone 9a. Your town's frost dates vary; enter your ZIP for dates built on your nearest weather station.
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Put these dates to work
The plant profile covers spacing, light, water, soil, and source-backed timing details. The growing guide covers preparation, care, and harvest technique.